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Croms MailPress

By croms·
A powerful and flexible email delivery manager for WordPress. Supports multiple SMTP profiles, external SMTP relays, and high-speed API integrations.
Version
1.0.1
Last updated
Jun 16, 2026
Croms MailPress

Croms MailPress is a comprehensive email delivery solution designed to provide flexible, reliable, and high-performance mailing capabilities directly from your WordPress dashboard. Whether you need to send personalized newsletters, transactional emails, or bulk announcements, this plugin ensures your emails reach their destination securely and efficiently.

Key Features

  • Scheduled Sending: Easily schedule your emails to be sent at a specific date and time, perfect for newsletters and timed announcements.
  • Recipient Management & CSV Import: Send emails to manually entered addresses or upload a CSV file with up to 100,000 recipients.
  • Detailed History & Resending: Track the status of every email sent. View success/error logs and easily retry failed deliveries with a single click.
  • Flexible “FROM” Profiles: Register and manage multiple sender addresses and their corresponding SMTP server settings. Switch between them seamlessly when composing emails.
  • Opt-out & Bounce Handling: Manage user subscriptions with a dedicated opt-out list. Manually or automatically classify emails as allowed, paused, hard bounce, soft bounce, or blacklisted.
  • Safe Opt-out Page Customization: The [croms_mailpress_optout] shortcode uses a fixed plugin-controlled template. Administrators can change labels, messages, layout preset, color preset, width, and email visibility without saving arbitrary HTML, CSS, JavaScript, or PHP.
  • Multiple Sending Methods: Choose between individual SMTP profiles (Account-based), external SMTP Relays, or high-speed API Integrations for massive scale delivery.
  • Bulk Delivery via Cron: Easily schedule and dispatch large volumes of emails using external Cron jobs. The built-in setup guide helps you configure Cron for both rental servers (e.g., cPanel, XServer) and VPS/Cloud environments.

Opt-out Page Design Customization

The public opt-out form generated by [croms_mailpress_optout] does not provide custom code textareas. This is intentional for WordPress.org review compatibility and user safety. Use the structured settings in Mail Manager > General Settings to adjust the heading, explanatory text, button labels, success messages, design preset, color preset, width, and whether the recipient email address is displayed.

For advanced visual customization, add CSS through WordPress core features such as Appearance > Customize > Additional CSS or the Site Editor’s CSS tools. The fixed template exposes stable classes such as .croms-mailpress-optout, .croms-mailpress-optout__card, .croms-mailpress-optout__title, .croms-mailpress-optout__notice, and .croms-mailpress-optout__button.

External Services / Third-Party APIs

This plugin supports optional delivery through the third-party service smtp-relay.jp (Croms SMTP Relay Service).

  • What the service is used for: The service is used only when the site administrator selects either the SMTP Relay delivery method or the API Integration delivery method in this plugin. It is also used when the administrator runs the relay/API connection test from the plugin settings screen.
  • What data is sent and when:
    • SMTP Relay: When the SMTP Relay delivery method is selected and an email is sent, the plugin connects to the configured *.smtp-relay.jp SMTP server and sends the email for relay delivery. This includes the sender address, recipient address, subject, message body, and any attachments included in the email. When the administrator runs the SMTP relay connection test, the plugin connects to the configured *.smtp-relay.jp server to verify connectivity.
    • API Integration: When the API delivery method is selected and an email is sent, the plugin sends a JSON request to the configured https://*.smtp-relay.jp/receive.php endpoint. This request includes the API key in the request header, the sender name and address, recipient address, subject, HTML message body, and any attachments included in the email. When the administrator runs the API connection test, the plugin sends a test request to the configured API endpoint that includes the API key and uses the site’s administrator email address as the sender and recipient for the test payload.
  • Service provider links: Please review the service terms and privacy policy before using the external delivery methods:
    • Terms of Service: https://wp.croms.jp/smtp-relay-terms/
    • Privacy Policy: https://wp.croms.jp/smtp-relay-privacypolicy/
Freeon paid plans
Tested up to
WordPress 7.0
This plugin is available for download for your site.